RESUMOObjetivou-se avaliar a adaptabilidade fisiológica de 73 matrizes suínas híbridas em lactação ao ambiente quente. As fêmeas foram distribuídas em delineamento inteiramente casualizado, num esquema fatorial de 5 x 4 x 4, sendo, cinco ordens de parto -OP (1ª, 2ª, 3ª, 4ª e 5ª), quatro momentos em relação ao parto (quatro dias antes e 3, 10 e 17º dia depois) e quatro horas do dia (8, 12, 16 e 20 h). A temperatura retal (TR) oscilou com a hora do dia, a OP, e o momento de avaliação, sendo maior às 16 h, em primíparas e na fase inicial da lactação. A freqüência respiratória permaneceu elevada, principalmente entre as 12 e 16 h do dia em fêmeas jovens. Conclui-se que o calor intenso entre 12 e 16 h conduz aos animais ao desconforto térmico, sendo as primíparas a categoria de menor adaptabilidade.Termos para indexação: Adaptabilidade, frequência respiratória, temperatura retal. ABSTRACTThe aim was to assess the physiological adaptability of 73 hybrid female swine in lactation in the hot climate. The females of 1 st , 2 nd , 3 rd , 4 th , and 5 th parturition orders (PO) were used, distributed in a completely randomized outline, in a factorial arrangement of 5 x 4 x 4, being five PO (1 st , 2 nd , 3 rd , 4 th , and 5 th ), four moments in relation to the delivery (four days before, and on the 3 rd , 10 th and 17 th day after), and four hours a day (8, 12, 16 and 20 h). The rectal temperature oscillated according to the hour of day, the PO, and the moment of evaluation, being greater at 16 h, in primiparous, and in the initial phase of lactation. The breathing frequency remained elevated, mainly between 12 and 16 h, in young females. One concluded that the intense heat between 12 and 16 h leads the animals to the thermal discomfort, mainly the category of smaller adaptability.Index terms: Adaptability, breathing frequency, rectal temperature. INTRODUÇÃOA suinocultura passou por uma série de transformações nas últimas décadas, devido, principalmente, aos avanços registrados na genética e na nutrição. Mas, recentemente, o controle das condições ambientais tornou-se uma preocupação mundial, no sentido de promover o bem-estar dos animais e maximizar a produção.Para matrizes suínas em lactação, a zona de conforto situa-se entre 12 e 22ºC (BLACK et al., 1993). Nessas condições, a temperatura retal permanece com valores médios de 38,6ºC e freqüência respiratória ente 26 a 27 mov/min (QUINIOU & NOBLET, 1999). Porém, quando submetidas a temperaturas ambientais elevadas, as matrizes manifestam desconforto, modificando seu comportamento e desencadeando mecanismos controladores ligados, diretamente, às respostas fisiológicas, na tentativa de dissipar o calor e manter a homeostase térmica. Em conseqüência, são verificadas reduções no consumo alimentar voluntário, perda de peso e da condição corporal, baixo desempenho das matrizes e suas leitegadas ao desmame, e falhas reprodutivas subseqüentes.Estudo desenvolvido em câmaras climáticas revelou que as matrizes respondem imediatamente ao estresse calórico aumentando as temperaturas...
Cysteine is a nonessential amino acid in poultry nutrition. Poultry diets are deficient in cysteine, but the bird's cysteine need is met through the transsulfuration pathway (TSP) where homocysteine is converted to cysteine: a process catalyzed by cystathionine β-synthase (CBS) and cystathionine γ-lyase (CTH). Cysteine is also a major component of keratinized protein found in feathers, but the extent to which cysteine is involved in feather and skin development in poultry is unknown. We randomly assigned chicks to control and treatment (control diet plus 100 mg/kg body weight of propargylglycine which is an inhibitor of CTH) diets. The thickness of skin layers, primary feather follicle parameters, growth, and mRNA expression of CBS and CTH were measured. Inhibition of TSP corresponded with the upregulation of liver mRNA of both CBS and CTH and reduction in growth from 35 to 40 days of age. The epidermis thickness, feather follicle length, and diameter were reduced from 10 to 40 days of age. Incorporation of cysteine into keratinized protein may be more sensitive to the level of available cysteine than into nonkeratinized proteins. Thus, disruption of the TSP could affect the thermoregulatory ability of the bird.
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